Abiotic stresses influence the transcript abundance of PIP and TIP aquaporins in Festuca species

Abstract

Festuca arundinacea and F. pratensis are the models in forage grasses to recognize the molecular basis of drought, salt and frost tolerance, respectively. Transcription profiles of plasma membrane intrinsic proteins (PIPs) and tonoplast intrinsic proteins (TIPs) aquaporin genes were obtained for leaves of Festuca species treated with different abiotic stimuli. F. arundinacea plants were exposed to drought and salt stress, whereas F. pratensis plants were cold-hardened. Changes in genes expression measured with use of real time qRT-PCR method were compared between two genotypes characterized with a significantly different level of each stress tolerance. Under drought the transcript level of PIP1;2 and TIP1;1 aquaporin decreased in both analyzed F. arundinacea genotypes, whereas for PIP2;1 only in a high drought tolerant plant. A salt treatment caused a reduction of PIP1;2 transcript level in a high salt tolerant genotype and an increase of TIP1;1 transcript abundance in both F. arundinacea genotypes, but it did not influence the expression of PIP2;1 aquaporin. During cold-hardening a decrease of PIP1;2, PIP2;1, and TIP1;1 aquaporin transcripts was observed, both in high and low frost tolerant genotypes. The obtained results revealed that the selected genotypes responded in a different way to abiotic stresses application. A reduced level of PIP1;2 transcript in F. arundinacea low drought tolerant genotype corresponded with a faster water loss and a lowering of photosynthesis efficiency and gas exchange during drought conditions. In F. pratensis, cold acclimation was associated with a lower level of aquaporin transcripts in both high and low frost tolerant genotypes. This is the first report on aquaporin transcriptional profiling under abiotic stress condition in forage grasses.Electronic supplementary materialThe online version of this article (doi:10.1007/s13353-017-0403-8) contains supplementary material, which is available to authorized users.

TIP Aquaporins in Plants: Role in Abiotic Stress Tolerance

“…In Festuca pratensis, TIP cold acclimation was associated with a lower transcript level of the FpTIP1;1 gene in the leaves in both the high and low frost-tolerant genotypes. The authors concluded that the down-regulation of these isoforms during the exposure to cold may be one of the cold-acclimation components that prevents frost-induced cellular dehydration [90]. A similar pattern of expression was observed in roots in rice (Oryza sativa L.) under cold treatment.…”

“…In turn, in Festuca arundinacea, the plants were exposed to salt stress by irrigating them with 250 mM NaCl solution over 21 days, which resulted in an increase in the abundance of the FaTIP1;1 transcript in two contrasting salt tolerance genotypes compared to the control conditions. This increase was noticed earlier on day six of the NaCl treatment in the high-salt tolerant (HST) genotypes and later on day 11 in the low-salt tolerant (LST) genotype [90].…”

“…Moreover, in barley (Hordeum vulgare L.), the expression of five HvTIP aquaporins in leaves: HvTIP1;1, HvTIP1;2, HvTIP2;1, HvTIP2;2 and HvTIP2;3 was down-regulated after ten days of severe drought treatment [89]. In turn, in Festuca species, the transcript level of the TIP1;1 aquaporin decreased in leaves after 11 days of a water deficit [90]. The possible functional role of coffee (Coffea arabica L.) TIPs in in regulating the water balance has been explored by measuring the TIP gene expression in leaf and root tissues that had been subjected to drought [91].…”

To cope with drought: two forage grass species – Festuca arundinacea and F. glaucescens can activate similar survival strategies although they differ with molecular response

“…In F. arundinacea, drought resistance is mostly manifested by a drought avoidance strategy which relies on the development of deep root system, leaf rolling and a rapid stomatal closure (5,11). However, our earlier experiments revealed that F. arundinacea could also develop a drought tolerance strategy mainly associated with the adjustment of leaf metabolism to water deficit in plant tissues (5,6). On the other hand, F. glaucescens was described earlier as a species characterized mainly by a metabolism slowdown and a reduction of growth associated with a quiescence under drought conditions, followed by a further recovery after stress cessation, which enables it to survive and to resume the growth following irrigation (12,13).…”

“…Our previous studies revealed that Festuca species could be successfully used as models to precisely dissect mechanisms of resistance to a wide range of abiotic stresses in a group of forage grasses (e.g. 3,4,5,6,7,8,9).…”